When you define a function, or import one, into a Perl package, it will naturally also be available as a method. This does not per se cause problems, but it can complicate subclassing and, for example, plugin classes that are included via multiple inheritance by loading them as base classes.

The namespace::clean pragma will remove all previously declared or imported symbols at the end of the current package's compile cycle. Functions called in the package itself will still be bound by their name, but they won't show up as methods on your class or instances.

By unimporting via no you can tell namespace::clean to start collecting functions for the next use namespace::clean; specification.

You can use the -except flag to tell namespace::clean that you don't want it to remove a certain function or method. A common use would be a module exporting an import method along with some functions:

Note that the technique used by this module relies on perl having resolved all names to actual code references during the compilation of a scope. While this is almost always what the interpreter does, there are some exceptions, notably the sort SUBNAME style of the sort built-in invocation. The following example will not work, because sort does not try to resolve the function name to an actual code reference until runtime.

will remove subA and subB from $cleanee. Note that this will remove the subroutines immediately and not wait for scope end. If you want to have this effect at a specific time (e.g. namespace::clean acts on scope compile end) it is your responsibility to make sure it runs at that time.

will remove the foo symbol from $SomePackage for run time lookups (e.g., method calls) but will leave the entry alive to be called by already resolved names in the package itself. namespace::clean will restore and therefor in effect keep all glob slots that aren't CODE.

A test file has been added to the perl core to ensure that this behaviour will be stable in future releases.

Just for completeness sake, if you want to remove the symbol completely, use undef instead.